/* ──────────────────────────────────────────────────────────────────────────
   cpp-container-optimization-tutorial — site.css

   Class system mirrors patterncatalyst/hummingbird-tutorial so the visual
   language is consistent across the patterncatalyst Jekyll family. Every
   selector here is tied to a structural class produced by the layouts and
   includes in this repo; nothing styles raw HTML beyond minimal resets.

   Color tokens follow a light/dark system that respects OS preference.
   ────────────────────────────────────────────────────────────────────── */

:root {
    /* Light theme tokens. Site stays light regardless of OS preference —
       matches hummingbird-tutorial's behaviour. To opt back into auto
       dark mode, see the commented block at the bottom of this file. */
    color-scheme: light;

    --bg:           #fdfbf7;
    --bg-soft:      #f4efe6;
    --bg-card:     #ffffff;
    --fg:          #1a1a1a;
    --fg-muted:    #4a4a4a;
    --fg-faint:    #767676;
    --accent:      #c0392b;       /* deep red — performance/heat */
    --accent-soft: #f4d2cd;
    --accent-fg:   #ffffff;
    --rule:        #e6dfd2;
    --code-bg:     #2b2a26;
    --code-fg:     #f7f3ec;
    --shadow-sm:   0 1px 2px rgba(0, 0, 0, .04), 0 1px 3px rgba(0, 0, 0, .06);
    --shadow-md:   0 4px 8px rgba(0, 0, 0, .06), 0 2px 4px rgba(0, 0, 0, .04);
    --shadow-lg:   0 10px 30px rgba(0, 0, 0, .08), 0 6px 14px rgba(0, 0, 0, .06);
    --radius:      8px;
    --radius-lg:   14px;
    --maxw:        1080px;
    --maxw-prose:  720px;
    --t-fast:      150ms ease;
    --t-normal:    250ms ease;
    --font-sans:   -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
                   Arial, "Noto Sans", sans-serif;
    --font-mono:   ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
                   "Liberation Mono", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--fg);
    font: 16px/1.6 var(--font-sans);
    -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover, a:focus { text-decoration: underline; }

img, svg, object { max-width: 100%; height: auto; display: block; }

hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0; }

/* ── Layout primitives ───────────────────────────────────────────────── */

.container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.container-prose {
    max-width: var(--maxw-prose);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section        { padding: 4rem 0; }
.section-tight  { padding: 2rem 0; }

.section-heading {
    font-size: 1.75rem;
    margin: 0 0 .5rem;
    letter-spacing: -.01em;
}

.section-sub {
    color: var(--fg-muted);
    font-size: 1.05rem;
    max-width: var(--maxw-prose);
    margin: 0 0 2rem;
}

/* ── Site chrome (header, footer) ────────────────────────────────────── */

.site-header {
    position: sticky; top: 0; z-index: 50;
    background: color-mix(in srgb, var(--bg) 90%, transparent);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--rule);
}
.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: .85rem 0;
}
.site-header__brand {
    font-weight: 600;
    color: var(--fg);
    font-size: 1.05rem;
}
.site-header__brand:hover { text-decoration: none; color: var(--accent); }
.site-header__brand-emoji { margin-right: .35rem; }

.site-nav {
    display: flex; gap: 1.25rem; align-items: center;
}
.site-nav a {
    color: var(--fg-muted);
    font-size: .95rem;
    border-bottom: 2px solid transparent;
    padding: .25rem 0;
    transition: color var(--t-fast), border-color var(--t-fast);
}
.site-nav a:hover { color: var(--fg); text-decoration: none; }
.site-nav a.is-current {
    color: var(--fg); border-bottom-color: var(--accent);
}
.site-nav__spacer { flex: 1; }

.site-footer {
    border-top: 1px solid var(--rule);
    margin-top: 4rem;
    padding: 2.5rem 0 3rem;
    color: var(--fg-muted);
    font-size: .92rem;
}
.site-footer__inner {
    display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: space-between;
}
.site-footer a { color: var(--fg-muted); }
.site-footer a:hover { color: var(--accent); }

/* ── Hero (homepage and listing pages) ───────────────────────────────── */

.hero {
    padding: 5rem 0 3.5rem;
    background:
        radial-gradient(circle at 80% -10%, var(--accent-soft) 0%, transparent 35%),
        var(--bg);
}
.hero--compact { padding: 3rem 0 2rem; }

.hero__eyebrow {
    display: inline-block;
    padding: .25rem .65rem;
    background: var(--accent-soft);
    color: var(--accent);
    border-radius: 999px;
    font-size: .8rem;
    font-weight: 600;
    letter-spacing: .04em;
    text-transform: uppercase;
    margin-bottom: 1rem;
}

.hero h1 {
    font-size: clamp(2rem, 4vw + .5rem, 3.4rem);
    line-height: 1.1;
    letter-spacing: -.025em;
    margin: 0 0 1.25rem;
    max-width: 18ch;
}

.hero__lead {
    font-size: 1.15rem;
    color: var(--fg-muted);
    max-width: 60ch;
    margin: 0 0 2rem;
}

.hero__chips {
    display: flex; flex-wrap: wrap; gap: .5rem; margin: 0 0 2rem;
}
.chip {
    display: inline-block;
    padding: .3rem .75rem;
    background: var(--bg-soft);
    border: 1px solid var(--rule);
    border-radius: 999px;
    font-size: .85rem;
    color: var(--fg-muted);
}
.chip--accent {
    background: var(--accent-soft);
    border-color: transparent;
    color: var(--accent);
    font-weight: 600;
}

.hero__cta { display: flex; flex-wrap: wrap; gap: .75rem; }

.btn {
    display: inline-flex;
    align-items: center;
    gap: .4rem;
    padding: .7rem 1.2rem;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: .95rem;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background var(--t-fast), color var(--t-fast),
                border-color var(--t-fast), transform var(--t-fast);
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn--primary {
    background: var(--accent);
    color: var(--accent-fg);
}
.btn--primary:hover { background: color-mix(in srgb, var(--accent) 85%, black); }
.btn--secondary {
    background: var(--bg-card);
    color: var(--fg);
    border-color: var(--rule);
}
.btn--secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* ── Stats strip on the homepage ─────────────────────────────────────── */

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 1rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}
.stat { text-align: center; }
.stat__value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--fg);
    line-height: 1;
}
.stat__label {
    display: block;
    color: var(--fg-muted);
    font-size: .85rem;
    margin-top: .35rem;
}

/* ── Card grid (homepage tutorial sections, examples list) ───────────── */

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1rem;
}
.card {
    display: block;
    padding: 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    color: inherit;
    transition: border-color var(--t-fast), box-shadow var(--t-fast),
                transform var(--t-fast);
}
.card:hover {
    text-decoration: none;
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}
.card__eyebrow {
    color: var(--fg-faint);
    font-size: .8rem;
    text-transform: uppercase;
    letter-spacing: .04em;
    margin-bottom: .5rem;
}
.card__eyebrow strong { color: var(--accent); font-weight: 700; }
.card__title { margin: 0 0 .4rem; font-size: 1.1rem; }
.card__num {
    /* Two-digit zero-padded section number prefix, in the accent red,
       monospace so the column edge always lines up between cards. */
    display: inline-block;
    margin-right: .5em;
    color: var(--accent);
    font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
    font-weight: 700;
}
.card__desc  { margin: 0; color: var(--fg-muted); font-size: .94rem; }
.card__meta {
    display: flex; gap: 1rem; margin-top: .85rem;
    color: var(--fg-faint); font-size: .85rem;
}

/* doc-card variant (for the "reference" cards on homepage) */
.doc-card {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.1rem;
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    color: inherit;
    transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.doc-card:hover {
    text-decoration: none;
    border-color: var(--accent);
    box-shadow: var(--shadow-sm);
}
.doc-card__icon {
    font-size: 1.4rem;
    width: 2rem;
    flex-shrink: 0;
    text-align: center;
}
.doc-card__title { display: block; font-weight: 600; margin-bottom: .15rem; }
.doc-card__desc {
    display: block; color: var(--fg-muted);
    font-size: .92rem; line-height: 1.45;
}

/* ── Tutorial layout (single doc page, sidebar-free) ─────────────────── */

/* Tutorial pages render against a pure white background, distinct
   from the warm cream hero/landing surfaces, matching hummingbird-
   tutorial's reading-page convention. The .tutorial wrapper paints
   white edge-to-edge under the page; the body's --bg cream peeks
   through only on landing/gallery pages. */
.tutorial {
    padding: 2.5rem 0;
    background: #ffffff;
}

.tutorial__main { min-width: 0; }      /* prevent overflow on long lines */

.tutorial__header {
    margin: 0 0 2.5rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--rule);
}

/* Breadcrumb above the title: small, gray, "/"-separated.
   Reads "Home / Tutorial / [page title]". */
.tutorial__breadcrumb {
    color: var(--fg-faint);
    font-size: 0.85rem;
    margin: 0 0 1.5rem;
}
.tutorial__breadcrumb ol {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.tutorial__breadcrumb li:not(:last-child)::after {
    content: '/';
    margin-left: 0.5rem;
    color: var(--fg-faint);
}
.tutorial__breadcrumb a {
    color: var(--fg-muted);
}
.tutorial__breadcrumb a:hover {
    color: var(--accent);
}

/* Title row: big red 2-digit section number on the left, page
   title (h1) flexes alongside it on the right. The number is
   monospace so the column edge always lines up between sections. */
.tutorial__title {
    display: flex;
    align-items: baseline;
    gap: 1rem;
    margin: 0;
}
.tutorial__num {
    font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
    font-size: 4rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
    flex-shrink: 0;
}
.tutorial__title h1 {
    font-size: 2rem;
    margin: 0;
    letter-spacing: -.015em;
    flex: 1;
}

.tutorial__lead {
    color: var(--fg-muted);
    font-size: 1.1rem;
    margin: 1rem 0 0;
}

/* Pill row: rounded chips for duration and section number,
   sitting just above the bottom rule of the header. */
.tutorial__meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 1.5rem 0 0;
}
.tutorial__pill {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    background: var(--bg-soft);
    border: 1px solid var(--rule);
    border-radius: 999px;
    font-size: 0.85rem;
    color: var(--fg-muted);
}

/* Inline section headings inside tutorial prose stay black; the
   accent shows up as a small red rule above each h2, matching
   hummingbird-tutorial. h3 stays plain black bold so the visual
   hierarchy still reads at a glance. */
.tutorial__main h2 {
    margin-top: 3rem;
    font-size: 1.4rem;
    letter-spacing: -.01em;
    color: var(--fg);
}
.tutorial__main h2::before {
    content: '';
    display: block;
    width: 2.5rem;
    height: 3px;
    background: var(--accent);
    margin-bottom: 1rem;
}
.tutorial__main h3 {
    margin-top: 2rem;
    font-size: 1.15rem;
    color: var(--fg);
}

.tutorial__main p,
.tutorial__main ul,
.tutorial__main ol { line-height: 1.65; }

.tutorial__main blockquote {
    margin: 1.5rem 0;
    padding: .9rem 1.2rem;
    background: var(--bg-soft);
    border-left: 3px solid var(--accent);
    border-radius: 0 var(--radius) var(--radius) 0;
    color: var(--fg-muted);
}

.tutorial__main table {
    width: 100%; border-collapse: collapse; margin: 1.25rem 0;
    font-size: .95rem;
}
.tutorial__main th, .tutorial__main td {
    border: 1px solid var(--rule);
    padding: .55rem .75rem;
    text-align: left;
    vertical-align: top;
}
.tutorial__main th { background: var(--bg-soft); font-weight: 600; }

.tutorial__pager {
    display: flex; justify-content: space-between; gap: 1rem;
    margin: 3rem 0 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--rule);
}
.tutorial__pager a {
    flex: 1;
    padding: 1rem 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    color: var(--fg);
    transition: border-color var(--t-fast);
}
.tutorial__pager a:hover { border-color: var(--accent); text-decoration: none; }
.tutorial__pager a.is-prev { text-align: left; }
.tutorial__pager a.is-next { text-align: right; }
.tutorial__pager .label   { display: block; color: var(--fg-faint); font-size: .8rem; }
.tutorial__pager .title   { display: block; font-weight: 600; margin-top: .25rem; }

/* ── Code blocks ─────────────────────────────────────────────────────── */

code {
    font: .9em var(--font-mono);
    background: var(--bg-soft);
    padding: .12em .35em;
    border-radius: 4px;
}
pre {
    background: var(--code-bg);
    color: var(--code-fg);
    padding: 1.1rem 1.25rem;
    border-radius: var(--radius);
    overflow-x: auto;
    line-height: 1.5;
    margin: 1.25rem 0;
    box-shadow: var(--shadow-sm);
}
pre code { background: transparent; padding: 0; color: inherit; font-size: .92em; }
.highlight pre { margin: 1.25rem 0; }

/* ── Diagram includes (inline .excalidraw partial) ───────────────────── */

.excalidraw-figure {
    margin: 2rem 0;
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius-lg);
    overflow: hidden;
}
.excalidraw-figure__svg {
    background: var(--bg);
    padding: 1.5rem;
}
.excalidraw-figure__svg img,
.excalidraw-figure__svg object { margin: 0 auto; }
.excalidraw-figure__caption {
    padding: .75rem 1.25rem;
    font-size: .92rem;
    color: var(--fg-muted);
    border-top: 1px solid var(--rule);
    background: var(--bg-soft);
    display: flex; justify-content: space-between; gap: 1rem;
    align-items: center;
}
.excalidraw-figure__caption a { font-weight: 500; }

/* ── Diagram gallery (diagrams.html) ─────────────────────────────────── */

.gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}
.gallery-card {
    background: var(--bg-card);
    border: 1px solid var(--rule);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}
.gallery-card__viewer {
    cursor: pointer;
    background: var(--bg);
    padding: 1rem;
    min-height: 180px;
    display: flex; align-items: center; justify-content: center;
    transition: background var(--t-fast);
}
.gallery-card__viewer:hover { background: var(--accent-soft); }
.gallery-card__viewer:focus { outline: 2px solid var(--accent); outline-offset: -4px; }
.gallery-card__body {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--rule);
}
.gallery-card__section {
    color: var(--accent); font-weight: 700; font-size: .85rem;
    letter-spacing: .04em; text-transform: uppercase;
}
.gallery-card__title { margin: .25rem 0; font-size: 1rem; }
.gallery-card__caption {
    margin: 0; color: var(--fg-muted); font-size: .9rem;
    line-height: 1.45;
}
.gallery-card__actions {
    margin-top: .85rem; display: flex; gap: .75rem;
    font-size: .85rem;
}

/* ── Modal (fullscreen diagram viewer) ───────────────────────────────── */

.modal[hidden] { display: none; }
.modal {
    position: fixed; inset: 0;
    background: rgba(0, 0, 0, .85);
    z-index: 100;
    display: flex; align-items: center; justify-content: center;
    padding: 2rem;
}
.modal__close {
    position: absolute; top: 1rem; right: 1.5rem;
    background: transparent;
    border: none;
    color: white;
    font-size: 2rem;
    cursor: pointer;
    line-height: 1;
}
.modal__inner {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    max-width: 95vw;
    max-height: 90vh;
    width: 1100px;
    display: grid;
    grid-template-rows: auto 1fr auto;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}
.modal__header { padding: 1.1rem 1.5rem; border-bottom: 1px solid var(--rule); }
.modal__title  { margin: 0; font-size: 1.1rem; }
.modal__caption { margin: .25rem 0 0; color: var(--fg-muted); font-size: .92rem; }
.modal__viewer {
    overflow: auto;
    padding: 1.5rem;
    background: var(--bg);
}
.modal__svg { width: 100%; height: 100%; min-height: 50vh; }
.modal__actions {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--rule);
    background: var(--bg-soft);
    display: flex; gap: .75rem;
}

/* ── Plan layout (reconciliation) ────────────────────────────────────── */

.plan { padding: 2.5rem 0 4rem; }
.plan h1 { font-size: 1.75rem; margin: 0 0 1rem; }
.plan__notice {
    background: var(--accent-soft);
    color: var(--accent);
    padding: .75rem 1.25rem;
    border-radius: var(--radius);
    margin: 0 0 2rem;
    font-size: .92rem;
}

/* ── Utilities ───────────────────────────────────────────────────────── */

.visually-hidden {
    position: absolute !important;
    height: 1px; width: 1px; overflow: hidden;
    clip: rect(0 0 0 0); white-space: nowrap;
}

/* ── Opt-back-in dark mode ───────────────────────────────────────────────
   Uncomment this block (and remove `color-scheme: light` from :root above)
   to follow the operating system's theme preference. We default to
   light-only because hummingbird-tutorial does, and visual consistency
   across the patterncatalyst family is more important than theme parity
   with the OS.

@media (prefers-color-scheme: dark) {
    :root {
        color-scheme:   dark;
        --bg:           #15171c;
        --bg-soft:      #1d2026;
        --bg-card:      #22262d;
        --fg:           #ececec;
        --fg-muted:     #b8b8b8;
        --fg-faint:     #828282;
        --accent:       #ff7568;
        --accent-soft:  #3a1f1c;
        --rule:         #2a2f37;
        --code-bg:      #0f1115;
        --code-fg:      #e6e2da;
    }
}
*/


/* Bibliography cross-reference matrix */
.biblio-matrix {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.95em;
}
.biblio-matrix th,
.biblio-matrix td {
    text-align: left;
    padding: 0.5rem 0.75rem;
    border-bottom: 1px solid var(--rule, #e5e1d6);
}
.biblio-matrix thead th {
    background: var(--bg-soft, #f5f0e0);
    border-bottom: 2px solid var(--rule, #e5e1d6);
}
.biblio-matrix tbody td:not(:first-child) {
    text-align: center;
    width: 14%;
    color: var(--accent, #b54a2c);
    font-weight: 600;
}
.biblio-matrix tbody tr td:first-child {
    width: 44%;
}